perf bench numa: Add more comment for -c option

Adding more commentary for -c/--show_convergence option, to explain how
the convergence is defined.

Before:
    -c, --show_convergence
                          show convergence details

Now:
    -c, --show_convergence
                          convergence is reached when each process \
	(all its threads) is running on a single NUMA node.

Suggested--by: Jiri Hladky <jhladky@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Hladky <jhladky@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1488732011-27384-1-git-send-email-jolsa@kernel.org
[ Rephrased a bit based on a IRC conversation with Jiri ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/bench/numa.c b/tools/perf/bench/numa.c
index 3083fc36282b564d3fc5da05864907c3ac222cf4..6bd0581de2985b9feff5746154f69097db16bc30 100644 (file)
--- a/tools/perf/bench/numa.c
+++ b/tools/perf/bench/numa.c
@@ -187,7 +187,8 @@ static const struct option options[] = {
        OPT_INCR   ('d', "show_details" , &p0.show_details,     "Show details"),
        OPT_INCR   ('a', "all"          , &p0.run_all,          "Run all tests in the suite"),
        OPT_INTEGER('H', "thp"          , &p0.thp,              "MADV_NOHUGEPAGE < 0 < MADV_HUGEPAGE"),
-       OPT_BOOLEAN('c', "show_convergence", &p0.show_convergence, "show convergence details"),
+       OPT_BOOLEAN('c', "show_convergence", &p0.show_convergence, "show convergence details, "
+                   "convergence is reached when each process (all its threads) is running on a single NUMA node."),
        OPT_BOOLEAN('m', "measure_convergence", &p0.measure_convergence, "measure convergence latency"),
        OPT_BOOLEAN('q', "quiet"        , &p0.show_quiet,       "quiet mode"),
        OPT_BOOLEAN('S', "serialize-startup", &p0.serialize_startup,"serialize thread startup"),